Need help doing division on a * l + o without going beyond l.

limit = l
number = n
offset = o
amount = a

I have a fixed limit(l).
I cannot calculate with number beyond limit(l), and i need to find the result of the division: a * l + o.
Because i cannot directly do a*l (that would give off a number beyond limit(l)), i will need to find how many times in the result a*l + o, limit(l) will be repeated (put it into a) and put the offset (or the remaining value that does not go beyond limit(l)) of it into offset(o).

I would appreciate a quick response. I can explain further if you do not understand.